Black Powder
Invented in ninthcentury China, this mix of potassium nitrate, charcoal, and sulfur is what makes fireworks (plus guns and explosives), well, work. In a traditional firework a lit fuse kicks off the reaction, igniting the powder in the bottom of the shell. As the potassium nitrate burns, it lets off oxygen. The O2 helps the charcoal and sulfur burn too, producing hot gases that hurl the firework into the sky. Seconds later, a delayed fuse reaches the center of the payload, igniting the main shell to unleash a spectacle of light and sound.
Metal Salts
The rockets’ red glare as fireworks burst in air is simple chemistry: luminescence! As pellets containing metal salts inside the payload heat up, their electrons get excited and release excess energy as light.…
